This invention relates to a mortise, (or plug-in) lock for locking a removable tooth replacement prosthesis with a part adapted to be firmly fixed in the jaw bone of a patient, the lock comprising a lock housing which is embedded in the tooth replacement prosthesis and in which a locking bolt is mounted so as to be displaceable so that one end thereof engages into a recess in a keeper fixed to the jaw bone.
Already known are various embodiments of mortise locks which serve to retain a removable tooth replacement prosthesis on a part of a tooth replacement assembly which is firmly fixed in the jaw bone. By operating such a mortise lock, the lock can be released, so that the tooth replacement prosthesis can be removed from the jaw.
The known mortise locks of this kind have the disadvantage that they have to be worked very precisely if the tooth replacement prosthesis is to be reliably fixed. An accurate snug fit, however, results in high frictional resistance, which impedes the mobility of the locking bolt and which, after fairly long use, abates as a result of wear.
In a particular known mortise lock (U.S. Pat. No. 1,008,028) the locking bolt is slotted, whereby its front end, which is insertable through a bridge into a tooth, is expanded and, upon the insertion of the locking bolt, is applied resiliently into its guide.
However, this mortise lock has the disadvantages that when the locking bolt is inserted, pressure is constantly exerted on the tooth into which it projects, and that the locking bolt can be withdrawn completely from its holder, whereby it can easily be lost. The object of the invention is, therefore, to provide a mortise lock suitable for locking a tooth prosthesis in place which even with frequent use ensures a good snug fit, without excessive precision work being necessary in producing the device.
The foregoing object is met in a mortise lock which includes a locking bolt having an encircling elastic collar which is movable with the bolt and is supported against the inner wall of the lock housing.
In an advantageous embodiment, the locking bolt has an encircling annular groove in which there is arranged a spring ring which projects at the curved surface of the bolt and abuts against the inner wall of the locking housing. This spring ring is preferably arranged releasably on the locking bolt.
In accordance with a preferred embodiment, the end face of the lock housing remote from the keeper, is connected releasably to the housing in which the locking bolt is displaceable. In the unlocked position, the inner surface of this end face is designed as a stop for the collar of the locking bolt.
In accordance with a further embodiment, arranged in the inner wall of the lock housing is an annular groove into which, in the locked position, the elastic collar or spring ring of the locking bolt engages.